The ankle joint in medicine is the joint between the tibia-fibula and the talus bones. In a more layman terminology the ankle also includes the joint between the talus and the calcaneus (the subtalar joint). A ligament injury to the ankle is the most common ligament injury and is one of the most common musculoskeletal injuries. Fortunately these injuries usually heal without long term problems. Sometimes, however, the ligaments do not heal in such a way to provide biomechanical stability to the ankle and this causes chronic instability of the ankle. This chronic instability and giving way of the ankle can lead to pain, reinjury and degeneration in the joint and arthritis. Several surgical procedures have been developed to repair the ligaments of the ankle with no clear consensus as to which one is the preferable.
The ligaments which are most commonly injured are on the lateral (outside) side of the foot and consist of the anterior talo-fibular ligament and the calcaneo-fibular ligament.
In order to diagnose an injury to the ligaments of the ankle a laxity test is performed on the ankle. Usually this is done by holding the tibia with one hand and the foot with the other hand. Then an anterior-posterior (forward and backward) or inversion-eversion (twisting inward and outward) load is applied to the foot and the resulting motion is observed. This technique is highly subjective and subject to error since it is difficult to distinguish between the motion with or without the injured ligaments.